1. Field of the Invention
The invention generally relates to an apparatus for treating a surface which apparatus is responsive to an operator to position a head assembly relative to the surface. In particular, the invention relates to a brush head positioning system for a floor scrubber in which the brush head carries rotating brushes for cleaning the floor and the position of the brush head relative to the floor is controlled.
2. Background of the Invention
When scrubbing floors, it is important to maintain a constant and continuous scrubbing action on the floor. Often times, the floor surface is uneven, requiring some means for adjusting the brush head to follow the contours of the floor surface. The goal is to provide an even scrub across the entire floor. Also, brushes and pads can wear or the operator may want to change to a different type of brush or pad with different heights. In any of these conditions, the brush head must be properly positioned to compensate for such variations.
In the past, several attempts have been made to provide a floor scrubbing system which accomplishes the above. For example, in some systems, an operator must manually reposition the brush head depending on the various varying factors noted above. It is also known that the torque of drive motors for driving brushes or other floor maintenance tools may be controlled in order to provide some type of consistency in the application of force to the floor. However, such torque control systems tend to adjust the torque based on the type of surface of the floor or based on the condition of the floor. As an example, when scrubbing concrete the surface texture can change dramatically with only slight variations in floor height. Such a system may over torque the application of a brush to a smooth concrete floor and may under torque the application of a brush to a rough concrete floor. In addition, a floor which has a sticky coating on it may be under torqued whereas a floor with a shiny coating on it may be over torqued. Therefore, monitoring torque or current drawn on brush motors for positioning the brush head is not necessarily an effective technique for accomplishing consistency in the application of force to the floor. This is because the torque or current draw is dramatically affected by variations in the friction between the brushes and the floor. Since the coefficient of friction of the surface may change dramatically, this causes similarly dramatic changes in the current or torque, which changes may be unacceptable. Changes in surface texture may or may not demand a change in torque or current in order to maintain a proper and consistent floor treatment.
Other systems have suggested a load cell to measure pressure. However, such systems are expensive and difficult to implement in a reliable, industrial grade apparatus.
Therefore, there is a need for a system which consistently positions the brush head relative to the floor surface so that the position is repeatable thereby permitting the repeatable and consistent cleaning of the floor surface. There is also a need for a system which is responsive to variations in the contours of floors so that height adjustments between the brush assembly and the floor can be accomplished automatically to compensate for such differences in floor height. There is also a need for such a positioning system that accommodates different side brushes and pads.